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Protein Shake vs Meal Replacement Shake

by Mara Welty October 20, 2023 7 min read

 Protein Shake vs Meal Replacement Shake

Whether you’re spending your free time building muscle at the gym or don’t have any free time at all, supplemental shakes such as protein shakes and meal replacement shakes offer a convenient way to meet your health goals.

That said, protein shakes are typically meant to help you bulk up. In other words, they pad your diet with extra calories and protein to assist muscle synthesis. Meal replacement shakes, on the other hand, are most often used to support nutritional intake and fat loss.

But there’s a lot more to explore when it comes to the protein shake vs meal replacement shake debate.

What Is a Protein Shake?

A protein shake is a type of drink that athletes use to support weight management, muscle growth, and recovery. It comes in a powdered form, which can be added to water, milk, milk alternatives or smoothies.

The most beneficial powders are those derived from milk. These include whey powder and casein powder. Research has found that whey powder may be the most effective among the two when it comes to:

  • Building and maintaining muscle mass
  • Supporting muscles after strength training
  • Helping muscles recover after heavy exercise

That said, milk-based protein powders do contain lactose, a glucose found in milk products that can cause digestive issues in people who are intolerant to the sugar. Fortunately, there are other types of protein powder available for those looking to avoid lactose. These include:

  • Egg protein powder – This is the optimal choice for those looking for a highly digestible protein powder. Egg protein also helps regulate appetite levels and increase feelings of fullness. And it’s not far behind whey protein powder in terms of its role in muscle health — a 2012 study of female participants found that women athletes who took egg protein supplement powder saw increases in lean muscle mass and muscle strength.
  • Pea protein powder – Pea protein powder is more effective at reducing appetite than both egg protein powder and casein protein shake powder. It’s also high in fiber and plays a significant role in increasing muscle thickness and strength, as well as workout performance.
  • Hemp protein powder – Hemp comes from the Cannabis sativa plant; however, it contains only trace amounts of THC, meaning it’s perfectly safe for athletes to use during training. Although there’s little evidence to suggest that hemp protein powder is highly effective for muscle gains, it is well-digested.
  • Brown rice protein powder – Studies have found that regular consumption of brown rice protein powder before a workout may support muscle strengthening, but results weren’t as promising as with whey protein powder.

Protein Shake Nutritional Values

The nutritional value of protein shakes will vary depending on brand. However, the U.S. Department of Agriculture (USDA) states that 100 grams of generic whey protein powder contains 79.05 grams of protein and 7.91 grams of carbohydrates, as well as:

  • Calcium
  • Iron
  • Potassium

In comparison, generic casein protein powder contains roughly 80 grams of protein per every 100 gram serving (similar to brown rice protein), with no carbohydrates. It also has calcium and potassium. Pea protein powder, on the other hand, contains about 86.36 grams of protein, while hemp protein has only 38.71 grams for every 100 gram serving. Egg protein powder contains 82.4 grams of protein, as well as various vitamins and minerals.

When to Take a Protein Shake

Can a protein shake replace a meal? No, it does not. For athletes who undergo regular exercise and strength training, studies have found that consuming a protein shake 15 to 60 minutes following a workout is the most effective strategy.

This theorized time frame is referred to as the anabolic window, or the protein window.

It's during this time that the body is working to repair tears in the muscles that occurred during exercises like weightlifting. More specifically, certain hormones and macronutrient proteins are released to create new cells and repair torn muscles.

Essentially, the primary role of proteins is to build new cells and repair old ones. For this reason, increasing your protein intake post-workout allows your body to enter a protein surplus (when accompanied by a well-rounded whole-food balanced diet). As a result, you can work out (which breaks down proteins) and still have enough protein to aid in muscle recovery following your gym trip.

For older athletes looking to prevent muscle loss, it’s recommended to consume protein consistently throughout the day (25 to 30 grams per meal). As such, you may want to complement your breakfast with a protein smoothie, indulge in an afternoon protein bar post-workout and then finish your night with a frozen protein shake dessert.

Studies have also found that consuming protein before bed can support muscle building and recovery since it’s easily digested and absorbed, making it more available to the body.

What Is a Meal Replacement Shake?

Rather than to support a workout, a meal replacement shake is designed to replace your regular meal like breakfast, lunch or dinner and help manage weight. Because of this, meal replacement powder shakes are chock full of various vitamins, minerals and macronutrients, including protein. So, if you are wondering how to eat healthy while traveling, a meal replacement shake might just be able help. Just be sure to double check if you can bring a protein powder on a plane.

Actually, like protein shakes, they’re primarily made from protein powders, such as whey and casein protein powders, as well as plant-based alternatives. Why is this the case?

Protein plays a critical role in appetite, and it’s more filling than carbohydrates and fats. More specifically, consuming proteins can lower the amount of ghrelin — the hunger hormone — that your body releases throughout the day. As such, it may also help support healthy weight loss efforts.

One study found that overweight women who increased their protein intake to 30 percent of their total consumed calories ate 441 less calories a day, on average. The body also uses more calories to digest protein.

Like protein shakes, meal replacement shakes can also promote muscle growth, in addition to:

  • Supporting bone health
  • Improving metabolism
  • Increasing fat burning
  • Lowering blood pressure
  • Supporting body repairs

Nutritional Value of Meal Replacement Shakes

Like protein shakes, the nutritional value of meal replacement shakes will vary depending on the brand. That said, you can count on meal replacement shakes to be rich in nutrients, such as:

  • Vitamin A – Supports the formation and maintenance of teeth, bones, soft tissues, mucous membranes and the skin.
  • Vitamin C – Acts as an antioxidant to support the health of the gums, teeth and body tissue.
  • Calcium – Plays a role in regulating blood clotting, muscle contractions and heart and nerve functions.
  • Iron – Supports growth and development and provides oxygen to the muscles.
  • Greens – Spinach, alfalfa, broccoli and the like help to nourish your body with essential vitamins, minerals and fiber that contribute to your overall well-being.
  • Essential fatty acids – Additions like flaxseed, chia seed and coconut help regulate the body’s inflammatory response, support cognitive function and even regulate bowel movements if they’re high in fiber.
  • Digestive enzymes – Amylase, lactase, neutral protease, lipase, bromelain and papain help support digestive processes in the body, ensuring the efficient breakdown and absorption of each nutrient from the foods we consume.
  • Pre- and probiotics – These supplemental live microorganisms help bolster your gut’s microbiome to support digestive and cognitive health.

When to Take a Meal Replacement Shake

Meal replacement powder shakes are most often consumed for weight loss support since protein can help increase your metabolism, reduce feelings of hunger and promote fat burning.

As previously explored, protein decreases the amount of ghrelin produced by the body, thus curbing feelings of hunger and cravings throughout the day. It also increases hormones that lower appetite levels, such as:

  • Glucagon-like peptide-1 (GLP-1)
  • Peptide YY (PYY)
  • Cholecystokinin (CCK)

As such, adding a protein-rich meal replacement shake can decrease the amount of calories you eat every day, potentially creating a calorie deficit. A calorie deficit refers to consuming fewer calories than your body burns — and it's essential to weight loss.

To support your weight loss efforts, consider consuming a protein-rich meal replacement shake in the morning to help curb appetite levels. You can also supplement your meal replacement drink with protein snacks throughout the day, which may include:

  • Nuts
  • Eggs
  • Greek yogurt
  • Cheese

Meal replacement shakes can also help build lean muscle. In this case, like protein shakes, it’s advised to consume your shake following a workout. This way, you can provide your body with enough protein to repair muscles efficiently and feel recovered for the next day of exercise.

Supplement Your Diet With INVIGOR8

Generally, both protein shakes and meal replacement shakes have the same foundation: protein. That said, meal replacement shakes are often fortified with additional micronutrients and macronutrients, making them sufficient and satisfactory meal replacements that also support lean muscle building and weight loss. Protein shakes, on the other hand, are primarily used to help strengthen muscles and aid in muscle recovery.

However, the INVIGOR8 Superfood Shake can do both.

This powerful shake contains 20 grams of whey protein with every serving, alongside a bounty of additional nutrients in four delicious flavors: Triple Chocolate Brownie, Natural Strawberry, French Vanilla and Himalayan Salted Caramel.

In addition to essential vitamins and minerals, the organic Superfoods powder also contains a green veggie complex, essential fatty acids, digestive enzymes and pre- and probiotics, as well as protein powder ingredientsto enhance cognitive and immune health.

Whether you’re interested in protein shakes or meal replacement shakes, you may also consider addinghydrolyzed collagen peptides. Hydrolyzed collagen peptides support cardiovascular performance and weight loss while also promoting lean muscle mass and strength. So, what are you waiting for? Take your first sip today.



  1. Healthline. The 7 Best Types of Protein Powder
  2. Healthline. When Is the Best Time to Take Protein?
  3. Healthline. What Is an Anabolic Window?
  6. USDA. Pea Protein Powder
  7. USDA. Hemp Protein Powder
  8. WebMD. What to Know About Meal Replacement Shakes
  9. USDA. Egg, white, dried, powder, stabilized, glucose reduced
  10. Healthline. 10 Science-Backed Reasons to Eat More Protein
  11. MedlinePlus. Vitamins

About the Author

 Mara Welty
Mara Welty

Mara Welty is a copywriter who specializes in health, wellness and CBD topics. With a background in journalism, she aims to deliver engaging, research-based content that builds trust and engages readers through informative storytelling.

The INVIGOR8 Weight-Loss Family

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